1. Field of the Invention
The subject of the present invention relates to fluid-moving turbomachinery.
2. Description of the Related Art
Turbomachinery comprises rotating, fluid flow dynamic devices for transferring momentum into or out of the flowing fluid. The present subject matter relates to turbines driven by moving fluid as well as powered rotors which move fluid. Often, the fluid under consideration will be air. However, the considerations discussed here and below apply to other fluids, and are not limited to air. Other fluids include liquids and gases other than air. Commonly, machines providing outflow in the axial direction, i.e., along the axis of rotation of the rotor, are referred to as fans. Machines providing radial flow, i.e., at right angles to the axis of rotation of the rotor, are referred to as blowers. In certain forms of machines, fan or blower rotating elements are referred to as rotors. In the present description, fans, blowers, rotors, and associated functional components are referred to collectively as fluid movers.
A significant application of prior art axial and radial flow fluid movers is the cooling of electronic components, particularly semiconductor processors and other circuits. It is desirable to provide small air moving machines for producing flow over semiconductor components or over heat sinks, heat pipes or other heat transfer components that are thermally connected to semiconductors. Small air moving machines in the present context refer to the sorts of machines used to cool electronics and which can fit, for example, in laptop computers. This description is used in contrast to large machines of the type used, for example, in industrial heat exchangers or other machines mounted in enclosures which do not have particular size constraints.
Experience has shown that effective fan and blower designs for large machines which are proportionately scaled down to produce a small machine to fit in a laptop computer suffer large decreases in efficiency. This experience is reported, for example, by Quin, D. et al., The Effect of Reynolds Number on Microfan Performance, Proceedings of the 2nd International Conference on Microchannels and Minichannels, June 2004. This is very problematic in small portable electronic equipment because battery life is reduced by fan or blower operation. Thus, turbomachinery that can be made small in size and more efficient than conventional turbomachinery is highly desired in the art.